On Monday Egypt's top prosecutor, Nabil Sadek, ordered an investigation and by evening the police had arrested seven people, most of whom were said to have waved rainbow flags. An official at Mr. Sadek's office said the seven had been charged with "promoting sexual deviancy" and could be detained for 15 days. The state paper Al Ahram said one of the men had been detained for posting approvingly on Facebook about the concert. "Legal actions against him are underway," the paper reported. On Monday, one man who had been photographed with a rainbow flag at the concert wrote on Facebook, "Had I raised the ISIS flag I wouldn't be facing half of what I am facing now."